1. Field of the Invention
The invention relates generally to an apparatus for controlling the delivery of gobs to glassware forming machines. More specifically, the invention relates to interceptor apparatus for selectively enabling or rejecting delivery of a gob to selected molds in a section of a multiple section glassware forming machine.
2. Description of the Prior Art
Prior art glassware forming machines of the individual section type form glassware from gobs of molten glass by the cyclic performance of a predetermined series of steps in each section of the machine. Each section generally contains one or more blank molds for receiving one gob per mold, means for performing a predetermined series of steps prior to transferring a parison to one or more corresponding blow molds within that section and means for performing another predetermined series of steps to form a final article of glassware. Each section periodically performs an identical series of steps sequentially in a predetermined firing order at phased times within the cycle of operation of the machine. In single gob machines, one gob is periodically distributed to each section which then produces one glassware article therefrom. In triple gob machines, three gobs are simultaneously distributed to each section which contains three sets of molds or mold pairs (i.e. corresponding blank and blow molds) and associated components for producing one glassware article from each gob.
Glassware forming machines generally operate in conjunction with a cyclically oscillating gob distributor for periodically and sequentially distributing gob groups (containing one or more gobs of molten glass) to each section, a feeder serving as a source of one or more streams of molten glass, shears for cutting each stream into gobs and an interceptor associated with each stream and interposed between the shears and the gob distributor for occasionally, as needed, intercepting the gobs to reject them and prevent them from passing to the distributor and on to a particular section. While the interceptor is sometimes considered as part of the gob distributor, as used herein it will be considered a separate mechanism. Prior art interceptors associated with multiple gob glassware forming machines are designed to operate simultaneously to either enable delivery of all gobs within the gob group or to disable same.
A prior art multiple gob interceptor is normally held retracted out of the way to enable the gobs to pass to the gob distributor. The motion of the interceptor between a retracted delivery position allowing the gobs to pass, and an extended intercept position rejecting gobs to a cullet chute, is controlled by a delivery enable signal associated with each section of the glassware forming machine. The delivery enable signal of a particular section is provided by that section's timing controller and is turned on at one predetermined point of the machine cycle and off at another predetermined point. During the on time gobs may be delivered to that section. Those skilled in the art will understand that gob delivery to that section at any other time must not occur because the section will be performing various other functions in order to produce finished glassware and will not be able to accept any gobs.
Each section of a glassware forming machine, must run through several cycles in order to stabilize each mold at the proper operating temperature to produce satisfactory glassware. In the operation of a forming machine prior to temperature stabilization there is a well-known tendency for the glassware to collapse when the blow molds open, thereby preventing the take out tongs from grasping the ware. The collapsed ware must be removed by the machine operator: a difficult task if all three molds of a section are active. Accessability to the inner mold is especially limited. Accordingly, it is an object of this invention that each mold pair be started individually, for example, the inner one first, so the operator may easily keep the molds free from collapsed glassware during the start up phase.
Additionally, there occasionally arises a need to stop glassware manufacture by a section because only one mold of that section is producing unsatisfactory glassware. In practice, the interceptor would be commanded to reject all gobs of the gob group intended for that section, thus unnecessarily ceasing production of satisfactory glassware in order to determine the cause of production of unsatisfactory glassware. Accordingly, another object of this invention is to individually control gob delivery to the molds within each section so that the operator may selectively enable delivery to only selected ones of the mold sets.
Examples of prior art interceptors may be seen in U.S. Pat. Nos. 2,047,507 and 3,594,146 showing a single interceptor associated with a single respective gob. U.S. Pat. No. 2,836,934 shows a single interceptor associated with two gobs simultaneously. There is no prior art interceptor disclosing means for controlling delivery of only selected ones of the gobs within a gob group.